Platen carriage of typewriting machines



Oct. 10, 1944. c. w. BRUMHILL 2,369,395

' PLATEN CARRIAGES OF TYPEWRITING MACHINES Filed Feb. 24, 1943 4 Sheets-Sheet 1 7620/ By i CI'.. l0, 1944. C, W BRUMHILL @360,19

` PLATENl CARRIAGES 0F TYPE'WRITING MACHINES Filed Feb. 24, 1.943 4 Sheets-Sheet 2 Inventor GLAU DE WQ BRUMHILL Gd., E0, 1944., Q W BRUMHILL 2,36,96

* PLATEN CARRIAGES OF TYPEWRITING MACHINES P led Feb. 24, 1943 4 Sheets-Sheet 5 FIGS.

In venlor UDE w. BRuMHsLL l061:. 10, 1944.., Vc; W BRUMHlLL 253,196

` PLATEN CARRIAGES OF TYPEWRITING MACHINES Filed Feb. 24, 1943 Sheets-$1991.14

Inventor CLAUDE w. BRUMHILL Patented Oct. 10, 1944 PLATEN CARRIAGE F TYPEWRITING MACHINES claude Wellington Brumhiu, Leicester, England, assgnor to The Imperial Typewriter Company, Limited, Leicester, England Application February 24, 1943, Serial No. 476,972 In Great Britain December 5, 1942 (C1. IS7-133) 10 Claims.

This invention concerns the platen carriages of typewriting machines and is particularly but noi-l exclusively concerned with the kind of carriage wherein the platen is displaceable between operative and inoperative positions.

Itis known in typewriting machines, particularly continuous stationery machines employed for manifolding, to provide the carriage with a tear-off knife against which a typed length of paper may be torn from the stationery supply. In general this knife should be located close above the typing station, and since the act of tearing off the paper imposesa considerable bending strain on it, it has tobe of substantial cross section. It has been found that a comparatively flat oblong section located in the main tangential to the periphery of the platen with one thin edge adjacent to the platen surface is suitable. The diiiculty arises, however, that the knife obscures at least some of the typewriting, and in billing and like operations it is often necessary for the operator to refer to the material just typed for Vthe purpose of transferring data to a calculating machine. Thereforeaccording to the present invention a typewriting machine carriage is provided with a tear-off knife at the front of the platen which knife is movable between an operative position in which it is located close to the typing station so that the paper passes between it and the platen, and an inoperative position in which it is displaced from the platen and exposes the typing to View. Y

In certain .continuous stationery machines embodying a carriage of the kind referred to above it is the practice to displace the platen to the inoperative position after the requisite length of `typing has been completed so that the carbons or other transfer sheets may be retracted between the sheets of paper with which they are interleaved, and then to restore the platen to the operative position and to tear off the typed paper against a knife. According to a further feature of the present invention a typewriting machine carriage of the kind referred to has a tear-olf knife normally located in the operative position close to the platen but movable between said `operative position and an inoperative position in which it is spaced from the platen, and auto- `matic means for causing the knife to assume its 'operative position when, subsequent to displacement' of the platen, the latter is returned to operative position. Preferably, the knife assumes its normal relation tothe platen prior to the latter reaching its operative position. Thus typing may proceed with the knife in the inoperative position in which the last few lines of typing are visible, the operator then moves the platen to inoperative position, retracts the carbons and upon or prior to the restoration of the platen to the operative position the knife automatically resumes its operative position in relation to the platen so that the typed paper may be torn off against it. This obviates separate movements by the operator for restoring the knife toits operative position, and for restoring the platen to the operative position, and is a considerable advantage in the operation of the machine.

Since, as has been explained, the pull of the paper on the knife during tearing-off is considerable it is desirable that releasable latching mechanism shall be provided for holding the knife in the operative position. IFurthermore, since it is necessary for the knife to remain in the inoperative position for a substantial period while typing proceeds it is further desirable that means shall be provided for retaining it in that position.

These and other features of the invention set out in the appended claims are incorporated in the construction which will now be described, as an example, with reference to the accompanying drawings, in which Figure 1 is an end view of a typewriter carriage incorporating the present invention;

Figure 2 is a plan showing the relevant parts thereof; l

Figures 3 and 4 are sections on the line 3--4 in Fi-g. 2, looking in the direction of the arrows, and showing the knife in the "open and closed positions respectively;v

Figures 5 and 6 are like sections on the line 5 6 in Fig. 2;

Figure 7 is a plan of the relevant parts at the right hand end of the carriage shown in Fig. 2 and illustrating the manual release of the knife lock;

Figures 8 and 9 are respectively, sections on the lines 8-8 and 9-9 vin Fig. 2; while Figure 10 is a View, similar to Figs. 5 and 6, but illustrating the action when the platen is swung to the inoperative position.

In Figure 1 the invention is shown as applied to the typewriter carriage described in British Patent Specification 548,198. For details reference may be made to said specification, but a brief description will be given herein and accorded the same reference numerals. The typewriter carrage I0 has, pivoted at the front thereof at 22 between the carriage ends 23, a sub-frame consisting of platen end plates 2liV connected by a paper table 29 in which sub-frame the platen Il arm forward. At each end of the sub-frame thereA is a lever 35 pivoted at 35 said levers being connected by a tubular member :31 to which the support arm 30 is attached. Thus when the support arm 30 is pulled forward said levers 36 are rocked about pivots 35 against the action of springs 38, the extent of movement being restricted by screws-42 passing through slots 4|. At least one lever 36 carries a projecting stud or roller 39 which is thus brought into contact with a platen clamping lever 4i! associated with a platen clamp 32,1said clamp and lever being pivoted to the carriage end 23 at 33 and being drawn by a spring 34 so that the clamp 32 normally overlies a roller 45 on the platen spindle I9. The lever 40 and clamp 3'2 are thereby moved to the left in Fig. 1, the extent of movement being determined by a screw 44 extending through a slot 43 into the carriage end. The pull on support arm 3|) therefore unlocks the platen clamping mechanism and'swings the platen upwards and forwards. In the return movement of the platen toits operative position the roller 45 on the spindle |9 makes contact with the arm 4i! and displaces the clamp 32 to `such an extent that the platen spindle |9 can pass freely into the cradles 46 provided 'for its reception in the carriage ends The knife 2| is of flat cross section, as will be appreciated from Figs. 3 to 6 and normally has -its tearing edge (which may beV serrated as shown in Fig. 2) located at 'the front of the visible platen in close proximity thereto and just above the typing station at vwhich the type characters strikey and which, as is well known vfor the type of carriage illustrated, is approximately on the horizontal diameter of the platen, so that the typed paper passes upwards between the platen'and knife. few rows of typing and it is therefore desirable that it shall be movable to what may be termed an open position in which it is spaced4 further away from the platen and is preferably positionededge-on to the platen so that all or nearly all the typing is visible to the operator. For this purpose the knife 2| is mounted by means of short side arms 68 on thepivot pins 22 by which the platen sub-frame is pivotally supported in the carriage for movement of the platen between operative and inoperative positions. The left-handside arm 60 is attached to acam member 6| (bestshown in Figs. 5, 6 and 8) formed asa cam with two flangs or ats 6|a and 6|b thereon located at an angle to one another andVV co-operating with Ya leaf spring 62 secured at 63 to the left-hand platen end plate 20. In the closed positionV of the knife 2| the free end of the spring y62 bears on the fiat 6|a as shown in Fig. and positions the knife 2| with a l1ug7|i4 (Fig. 3) bearing againstwastop pin projecting l from the right-handlcarriage end plate 23. Since in the closed or tearing off` position of the knife 2| the pull on thepaper being torn againstits edge would tend to swing it to the `openp'osition,`

releasable locking mechanism is provided 4for In this attitude the knife 2| obscures a locking the knife in the closed position. This locking mechanism comprises a latch member 68 pivoted at 69 to a part 20' on the right-hand platen end plate 20 and biased by a leaf spring 'I0 in the anti-clockwise direction, the extent of its movement being limited by a screw '|2 extending through a slot 13. Figs. Zand 7 show that a nose 68a on the said latch overlies a surface on the right-hand side arm 60 of the knife 2|.

The knife 2| is movable to the open position by a release lever 65 operation of which also serves to release the'said latch 68. The said release lever 65 is pivoted on the right-hand pivot pin 22 and is connected to the right-hand side arm 60 by a lost motion connection. In the illustrated embodiment this lost motion connection comprises a lpin 66 projecting from the inner face of the release lever 65 into an oversize hole E1 in the aforesaid right-hand side arm 68. In movement of the release lever 65 in the clockwise Y direction (Figs. 3 and 4) the lost motion between it and the knife serves to release the latch 68 after which (connection having been established) further movement of 'the release lever serves to swing the knife 2| about its pivots '22. In order to release the catch, at the outer face of the release lever 65 there is a conical projection or stud adapted to engagel with the upf-turned 'end 68h of a finger on the vlatch '68 so that, as the release lever v| rises,`a slope of the lprojection moves the latch 6/8 to the yright in Fig. 7,`and`so removes the retaining nose 68a from above the side arm 60. During the subsequent movement of' the knife to the open position the free end'of the spring 62 moves over the lobe or crest6|c`be tween the two flats 6|a, Glb and so causes the knife to rotate about Vits pivots '22 until it rreaches a position shown in Figs. 4`and 6 in which a stop Vlug a on the right-hand arm makes contact vwith the aforesaid stop pin and the free end of the spring 62 bears on the flat G'Ib.

The knife 2| may be restored to the closed position by manual operation'of the release lever 65. In the return movement vthefspring 62 rides off the flat 6|b 'and yover the 'crest Elc-so that during the final stages of the closing movement the knife springs home. The engagemen! of the latching mechanism is automatic. The righthand side arm 6|] engages'theinclined front edge of the nose 68a and'pusheslthe latch t'o the right (Figs. 2 and '7) `and the projection then jengages the upturned end 68D' andholds thelatch in the release position until the 'knife is fully home whereupon'thelat'ch"springs acrossto the latching position. c

According to the present invention, however, if the platen |'l is'raised'to its inoperative position with the knife 2| already. 'inits open position, the said knife isautomatically coupled in the closed position for return with the platen; 'Considering Figs. 6 and vr1Q,.iffthe platen is swung in Yan anti-clockwise "directionabout itsjpivotalY axis 22 it will be seen that the VVfree end of the spring 62 is lifted by the flat'Glb and rides over the lobe 6|c. This therefore causes rthe knife'to spring in a clockwise direction' until it reaches the closed'position with relation to the raised platen.

lIn this spring influenced movement of the knife,

Details of the pivoted mounting of the platen and knife are shown in Figs. 8 and 9. The pivot pins 22 extend through the platen end plates 20 into bushes 14 which are therefore clamped against said ends, and these bushes are rotatably mounted in the carriage end plates 23, desirably by roller bearings 15. The cam member El, to which the left hand side arm 60 is attached, rotates on the plain end of the left hand pin 22, but the right hand side arm 60 is attached to a bush |6I rotatable on the plain end of the right hand pin 22. Therefore the knife 2| is positioned endwise between bushes 14, The release lever 65 is attached to a sleeve 1B which encircles bush IBI and rotates in relation thereto within the limits of the lost motion connection.

I claim:

1. A typewriting machine carriage of the kind having a platen displaceable between operative and inoperative positions; having a tear-off knife normally located in operative position close to the platen but movable between said operative position and an inoperative position in which it is spaced from the platen, and means for causing the knife to assume its operative position when, subsequent to the displacement of the platen, the latter is returned to operative position.

2. A carriage according to claim l, having means for causing the knife to assume its normal relation to the platen prior to the displaced platen reaching its operative position.

3. A carriage according to claim 1, having releasable latching mechanism for holding the knife in the operative position.

4. A carriage according to claim 1, having releasable latching mechanism for holding the knife in its operative position and for connecting the knife in its normal relation to the platen when the platen is displaced to inoperative position subsequent to movement of the knife to inoperative position.

5. A typewriting machine carriage of the kind comprising a platen, and a sub-frame displaceable on the carriage to move the platen between operative and inoperative positions; having a tear-off knife, means mounting said knife in the sub-frame for movement in relation to the platen between a closed position in which it is located close to the platen and an open position in which it is spaced from the platen, a manual control for moving the knife between its two positions when the platen is in operative position, and releasable self-engaging latching mechanism for latching the knife in its operative position and for latching the displaced knife in its normal relation to the platen in the sub-frame, when the latter is displaced to inoperative position, for return with said sub-frame.

6. A carriage according to claim 5, having a manual control for releasing the latching mechanism and for displacing the knife.

'7. A carriage according to claim 5, having a manual control for releasing the latching mechanism and for displacing the knife, a lost-motion connection between said control and latching mechanism, and means whereby initial movement of the control, within the limits of said connection, releases the locking mechanism and subsequent movement displaces the knife.

8. A carriage according to claim 5, having spring means for biasing the knife, upon movement towards either of its two positions, into that position.

9. A typewriting machine carriage, comprising a platen, a sub-frame carrying the platen and pivotally mounted on the carriage for movement, about an axis which extends at the front of the platen parallel to the platen axis, between operative and inoperative positions, a tear-01T knife at the front of the platen and movable with the sub-frame, in movement of the latter between said two positions, to retain its normal location with respect tothe platen but also movable independently of the sub-frame between a closed position in which it is close to the platen and an open position in which it is spaced from the platen, manual means for moving said knife between open and closed positions, and automatic means for causing the knife to move to theclosed position when, the knife being in the open position, the sub-frame is moved out of and then into operative position.

10. A typewriting machine carriage of the kind referred to, having a platen-carrying sub-frame pivotally movable on the carriage between operative and inoperative positions, a tear-off knife movable separately from the platen about the same pivot between an operative position in which it is located near to the platen and an inoperative position in which it is spaced from the platen, a stop for the inoperative position of the knife, spring means for biasing the knife towards either of its two positions upon movement of the knife towards that position, self-engaging releasable latching mechanism for holding the knife in the operative position and for automatically latching the inoperatively-positioned knife to the platen sub-frame, for return therewith to the operative position, when the sub-frame is moved to the inoperative position, and a manual control for releasing the latching mechanism and for moving the knife between operative and inoperative positions.

CLAUDE WELLINGTON BRUMHILL. 

